import { Scrollbar as ProScrollbar } from '@hczy/ant-design-vue'
import getScrollbarWidth from '@/utils/get-scrollbar-width'
import './Container.less'

const tagAndTagSpacing = 4

export const TabsContainer = {
  name: 'ProTabsContainer',
  data() {
    return {
      left: 0
    }
  },
  computed: {
    reWrapStyle() {
      return `height:calc(100% + ${ getScrollbarWidth() }px);`
    },
    scrollWrapper() {
      return this.$refs.scrollContainer.wrap
    }
  },
  mounted() {
    this.scrollWrapper.addEventListener('scroll', this.emitScroll, true)
  },
  beforeDestroy() {
    this.scrollWrapper.removeEventListener('scroll', this.emitScroll)
  },
  methods: {
    handleScroll(e) {
      const eventDelta = -e.wheelDelta || e.deltaY * 40
      const $scrollWrapper = this.scrollWrapper
      $scrollWrapper.scrollLeft = $scrollWrapper.scrollLeft + eventDelta / 4
    },
    emitScroll() {
      this.$emit('scroll')
    },
    moveToTarget(currentTag) {
      const $container = this.$refs.scrollContainer.$el
      const $containerWidth = $container.offsetWidth
      const $scrollWrapper = this.scrollWrapper
      const tagList = this.$parent.$refs.tag

      let firstTag = null
      let lastTag = null

      // find first tag and last tag
      if (tagList.length > 0) {
        firstTag = tagList[0]
        lastTag = tagList[tagList.length - 1]
      }

      if (firstTag === currentTag) {
        $scrollWrapper.scrollLeft = 0
      } else if (lastTag === currentTag) {
        $scrollWrapper.scrollLeft = $scrollWrapper.scrollWidth - $containerWidth
      } else {
        // find preTag and nextTag
        const currentIndex = tagList.findIndex(item => item === currentTag)
        const prevTag = tagList[currentIndex - 1]
        const nextTag = tagList[currentIndex + 1]

        // the tag's offsetLeft after of nextTag
        const afterNextTagOffsetLeft = nextTag.$el.offsetLeft + nextTag.$el.offsetWidth + tagAndTagSpacing

        // the tag's offsetLeft before of prevTag
        const beforePrevTagOffsetLeft = prevTag.$el.offsetLeft - tagAndTagSpacing

        if (afterNextTagOffsetLeft > $scrollWrapper.scrollLeft + $containerWidth) {
          $scrollWrapper.scrollLeft = afterNextTagOffsetLeft - $containerWidth
        } else if (beforePrevTagOffsetLeft < $scrollWrapper.scrollLeft) {
          $scrollWrapper.scrollLeft = beforePrevTagOffsetLeft
        }
      }
    }
  },
  render() {
    return (
      <ProScrollbar
        ref="scrollContainer"
        class="pro-global-tabs-container"
        viewStyle={ 'height: 100%' }
        wrapStyle={ this.reWrapStyle }
        vOn:wheel_native_prevent={ this.handleScroll }
      >
        { this.$slots.default }
      </ProScrollbar>
    )
  }
}

export const ActionsContainer = {

}

export const TabsAndActionsContainer = {

}
